Highway sobriety roadblocks: When are they allowed?

In some parts of Tennessee, authorities used so-called sobriety checkpoints over the holiday weekend preceding the Fourth of July.

“Sobriety checkpoint” is another way of saying mandatory roadblock. It’s a tactic whereby police stop multiple cars going through certain intersections, based on a sequence such as stopping every other car. Police do this even if there is no probable cause or reasonable suspicion to believe that any particular driver is impaired by drugs or alcohol.

What is the legal basis for such roadblocks and what guidelines do police need to follow when using them?

U.S. Supreme Court case

The leading U.S. Supreme Court case on mandatory DUI roadblocks is now 27 years old. The case was called Michigan Dep’t of State Police v. Sitz.

The Fourth Amendment prohibits unreasonable seizures. In Sitz, both sides agreed that when police stop all vehicles at certain checkpoints, it is a seizure. The majority of the Court held that because of the state’s strong public safety interest in keeping impaired drivers off of the road, a brief delay at a checkpoint is justifiable.

In other words, the Court did not consider the roadblock stop to be an unreasonable seizure.

The Court acknowledged, however, that the right of the individual to be free of unreasonable interference from the police has to be balanced against the state’s interest. In a dissenting opinion, one of the justices argued that even a brief roadside stop is problematic when it is not based on any evidence giving rise to individualized suspicion.

Guidelines on checkpoints

In 13 states, sobriety checkpoints are not allowed. In those states, checkpoints may be prohibited by state law, prohibited by the state Constitution, or (as in Texas), prohibited based on the state’s interpretation of the federal Constitution.

Tennessee is not one of those states. Checkpoints are generally allowed in Tennessee, but that doesn’t mean anything goes. There are still guidelines that law enforcement must follow when setting up mandatory checkpoints or saturation patrols, such as publicizing checkpoints well in advance of when they are to be used.

We’ll discuss these guidelines on checkpoints more in an upcoming post. For now, we’ll simply note that there are federal guidelines from the National Highway Traffic Safety Administration on what steps authorities should follow in order to comply with the law.

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